Method of decreasing shrinkage in aluminum bronze castings



Patented Dec. 29, 1931,

UNITED STATE-S.

PATENT OFFICE ALADAB PAQZ, OF EAST CLEVELAND, bH'IO.

No Drawing. Application filed llovember 8, 1928, Serial No. 317,114,'am1 in Germany December 3, 1827.

This invention relates to alloys and has for its object the provision of a new metallic compositipn which shall combine in. itself the ready casting properties of red brass, to-= My improvements relateto alloys which contain copper as a chief constituent and especially copper and aluminum alloyed together. A binary alloy of these metals under the name of alumlnum bronze has been known for a great many years, but has exhibited the defect of a substantial casting difliculty, due in large part to excessive shrinkage which has produced flaws and unexpected failures so that the material was untrustworthy. From one point of view my invention can be considered as a method-of decreasing shrinkage in such aluminum bronze castings whereby such alloys are rendered commercially valuable. I have discovered that such a copper-aluminum alloy exhibits especially valuable properties when silicon and iron in proper quantities are both incorporated therein, producing a quaternary alloy. The quantity of these components can be varled within certain limits according to the desired character of the alloy. The following table illustrates the best proportions:

ganese' in smallamounts is desirable although it should generally be employed to an amount not above about 0.2 of 1% 'of the alloy, for example from L05 to 10%;

The alloy of my invention can for. example satisfactorily exhibit the following composition:

The iron can be employed in an available granular or powdered form or in t e form of some cheap, iron-containing, by-product.- I prefer to use an iron powder made from common cast-iron borings' 'As an iron-containing alloy one can employ ferro-silicon or ferro-manganese, and thereby obtain at the same time the advantage of these other valuable constituents, namely: silicon or mananese, in .the alloy. Other iron alloys such or exampleas ferro-titanium, ferro-boron, ferro-silicon-zirconium, and the like can be employed in case the peculiar effects due to these other alloying constituents are desired.

In the preparation of this allo I prefer first to melt the copper, then to ad the necessary quantity of silicon thereto, and afterwards the aluminum, either in the metal form or in the form of some specific alloy such as aluminum-silicon, copper-aluminum or the like. Last of all the iron is added either in the form of iron-powder or pulverized iron alloy as heretofore described. I have found it to be important that the iron or the iron-containing alloy should be added only at the end, that is to say after the addition of the other substances, especially after the addition of the aluminum.

I have further found it of special advantageto the introduction ofthe iron into the alloy to accomplish the same with the asslstance of certaindecomposable fluxing constituents of a type to become dissociated under the conditions of the operation with the production of an alkali metal and an evolved gaseous substance. A simple example of this is sodium fluoride, which is stirred mto the num powder which gives rise to the decomposition of the double fluoride throughout the mass as described in my Patents Nos. 1,464,-

625, 1,518,872, and 1,562,654 and the resulting sodium fluoride becomes still further broken up as described in my patents. The resulting action exhibits the two-fold advantageof favoring on the one hand to a considerable degree the alloying of the iron with the other constituents of the melt which is itself a difficult thing to accomplish andalso of producing evolved substances throughout the mass of alloy which affect a peculiarly eflicacious fluxing action by combining with the aluminum oxide and other non-metallic impurities. The amount of such fluxing constituents to be used can vary widely according to the conditions encountered. In any given case good results are obtained from the employment of relatively small quantities, while the use of a total of several percent of the weight of the alloy exhibits no disadvantage.

As an example, I take 100 parts of iron with 25 to 50 parts of sodium-silico-fluoride intimately mixed with a smaller proportion of aluminum powder, for example 5 to 10 parts.

This mixture may be incorporated with the iron which is to be introduced into the copper-aluminum-silicon-alloy and the whole stirred into the molten mass at one time or the iron constituent can be added separately and the fluoride-aluminum mixture either before or after.

Besides the previously mentioned alloying constituents it is possible in any given case to add still'other metallic modifying substances to the alloy and thereby change the character of the alloy in any desired manner.

The alloys produced according to my invention are very fine grained, and exhibit extraordinary strength, ductility. heat resistance, and resistance to corroding influences of various sorts especially against chemical corrosion. The alloy exhibits peculiarly advantageous casting properties, being easy to melt, showinglittle tendency towards segregation of the constituents, flows readily at low temperatures, copies the mold faithfully, and exhibits a very small degree of shrinkage, thereby enabling the production of successful castings whose different parts vary substantially in thickness. The castings can be worked according to any of the usual procedures. both hot and cold, as by forging, pressing, drawing, turning, cold-rolling and the like. By the use of proper heat-treatment and crystalcontrol-methods the characteristics of the alloy can be changed as regards its ductility, tensile strength, and rigidity.

It is a particular advantage of my inven- 1,sss,ea2

tion that I produce an alloy equal in casting qualities to the best red brass, without the employment of any expensive ingredients suchas tin, or any weakening ingredients such as lead, and this by the employment of such cheap and readily available materials as cast iron, and at the same time produce a product which is improved in its qualities of strength, ductility, and corrosion resistance.

Having thus described my invention what I claim is 1. Method of preparing an alloy containing copper 87% to 93%, aluminum 3% to 9%, silicon 1 to 2 and iron 1% to 3% characterized by first melting together the copper, aluminum and silicon, and finally adding the iron after the copper and aluminum have become melted together.

2. Method of preparing an alloy containing copper above 80%, aluminum above 6%, and between 1.5 and 2% of iron together with small amounts of one or more of the substances silicon, manganese, titanium, boron, zirconium, characterized by the incorporation of iron in the form of such an alloy that some of the components other than aluminum or copper shall be introduced thereby.

3. Method of preparing an alloy containing above 80% of copper together with a small amount of aluminum but greater than 6%, and a still smaller amount of iron but greater than 1%, characterized by the addition of the iron after the aluminum.

4. The method of preparing an alloy containing copper 87% to 93%, aluminum 3% to 9%, and iron 1% to 3% which contains the steps of first preparing an alloy of copper and aluminum and afterward adding iron thereto.

5. The method of preparing an alloy containing copper 87 to 93%, aluminum 3% to 9%, and iron 1% to 3% which contains the steps of adding the iron to the other molten metals only after the aluminum has been inc'orporated therewith and incorporating such iron in company with a fluxing material containing fluorine and an alkali metal.

6. Method of preparing an alloy containing copper 87 to 93%, aluminum 3% to 9%, silicon 1% to 2% and iron 1% to 3% characterized by'first meltin together the copper and aluminum and finaly adding the iron in the form of an alloy with silicon.

7. Method of preparing an alloy containing copper 87 to 93%,aluminum 3% to 9% silicon 1 to 2 and iron 1% to 3% an manganese-which contains the steps of first melting together the copperand aluminum, and finally adding the iron in the form of such an alloy that some of the other ingredi- CERTIFICATE OF CORRECTION.

Patent No. 1,838,632. Granted December 29, 1931, to

ALADAR PACZ.

It is hereby certified that error appears in the printed specification of the above numbered "patent requiring correction as follows: Page 2, line 115, claim 6, for "2%" read 2%%; and that the said Letters Patent should be read with this correction therein that the same-may confofm to the record of the case in the Patent Office. 7

Signed and sealed this 16th day of February, A. D. 1932.

M. J. Moore,

(Seal) Acting Commissioner of Patents. 

